/* ============================================================
   Particle Engine v2 — Documentation Theme
   Shared styles for guide/, api/, and examples/ pages
   ============================================================ */

:root {
  --bg: #0f172a;
  --bg-panel: #1e293b;
  --bg-secondary: #0f172a;
  --bg-tertiary: #1a1f2e;
  --bg-code: #151d2e;
  --border: #334155;
  --border-light: #475569;
  --fg: #e2e8f0;
  --fg-muted: #94a3b8;
  --fg-dim: #64748b;
  --accent: #38bdf8;
  --accent-soft: rgba(56, 189, 248, 0.13);
  --accent-strong: #0ea5e9;
  --accent-glow: rgba(56, 189, 248, 0.25);
  --success: #10b981;
  --success-soft: rgba(16, 185, 129, 0.13);
  --warning: #f59e0b;
  --warning-soft: rgba(245, 158, 11, 0.13);
  --error: #ef4444;
  --error-soft: rgba(239, 68, 68, 0.13);
  --purple: #a78bfa;
  --purple-soft: rgba(167, 139, 250, 0.13);
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, 'Liberation Mono', 'Courier New', monospace;
  --sidebar-width: 260px;
  --header-height: 56px;
  --content-max: 860px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  width: 100%;
  height: 100%;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* ---- Top Header Bar ---- */
.doc-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-height);
  background: linear-gradient(to bottom, #1e293b, #1a1f2e);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 20px;
  gap: 24px;
  z-index: 100;
}

.doc-header .logo {
  font-size: 15px;
  font-weight: 700;
  color: var(--fg);
  text-decoration: none;
  letter-spacing: -0.3px;
  white-space: nowrap;
}

.doc-header .logo span {
  color: var(--accent);
}

.doc-header nav {
  display: flex;
  gap: 4px;
  flex: 1;
}

.doc-header .nav-link {
  padding: 6px 14px;
  color: var(--fg-muted);
  font-size: 13px;
  font-weight: 500;
  text-decoration: none;
  border-radius: 6px;
  transition: all 0.15s;
}

.doc-header .nav-link:hover {
  color: var(--fg);
  background: var(--accent-soft);
}

.doc-header .nav-link.active {
  color: var(--accent);
  background: var(--accent-soft);
}

.doc-header .search-box {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--fg-dim);
  font-size: 13px;
  cursor: pointer;
  transition: border-color 0.15s;
}

.doc-header .search-box:hover {
  border-color: var(--border-light);
}

.doc-header .search-box kbd {
  font-family: var(--font-sans);
  font-size: 11px;
  padding: 1px 5px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--fg-dim);
}

/* ---- Layout: Sidebar + Content ---- */
.doc-layout {
  display: flex;
  margin-top: var(--header-height);
  min-height: calc(100vh - var(--header-height));
}

/* ---- Sidebar ---- */
.doc-sidebar {
  position: fixed;
  top: var(--header-height);
  left: 0;
  bottom: 0;
  width: var(--sidebar-width);
  background: var(--bg-panel);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 16px 0;
  z-index: 50;
}

.doc-sidebar::-webkit-scrollbar { width: 4px; }
.doc-sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }

.sidebar-section {
  margin-bottom: 8px;
}

.sidebar-section-title {
  padding: 8px 20px 4px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--fg-dim);
}

.sidebar-link {
  display: block;
  padding: 5px 20px 5px 24px;
  color: var(--fg-muted);
  font-size: 13px;
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: all 0.12s;
}

.sidebar-link:hover {
  color: var(--fg);
  background: rgba(56, 189, 248, 0.04);
}

.sidebar-link.active {
  color: var(--accent);
  border-left-color: var(--accent);
  background: var(--accent-soft);
}

.sidebar-link.sub {
  padding-left: 36px;
  font-size: 12px;
}

/* ---- Main Content ---- */
.doc-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  padding: 40px 48px 80px;
  max-width: calc(var(--content-max) + var(--sidebar-width) + 96px);
}

.doc-content > * {
  max-width: var(--content-max);
}

/* ---- Typography ---- */
h1 {
  font-size: 32px;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: var(--fg);
  margin-bottom: 8px;
  line-height: 1.2;
}

.page-subtitle {
  font-size: 17px;
  color: var(--fg-muted);
  margin-bottom: 32px;
  line-height: 1.5;
}

h2 {
  font-size: 22px;
  font-weight: 700;
  color: var(--fg);
  margin: 48px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
  letter-spacing: -0.3px;
}

h2:first-of-type {
  margin-top: 0;
}

h3 {
  font-size: 17px;
  font-weight: 600;
  color: var(--accent);
  margin: 32px 0 12px;
}

h4 {
  font-size: 14px;
  font-weight: 600;
  color: var(--fg);
  margin: 20px 0 8px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

p {
  margin-bottom: 16px;
  color: var(--fg-muted);
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

strong {
  color: var(--fg);
  font-weight: 600;
}

/* ---- Code ---- */
code {
  font-family: var(--font-mono);
  font-size: 13px;
  background: var(--accent-soft);
  color: var(--accent);
  padding: 2px 6px;
  border-radius: 4px;
}

pre {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px 20px;
  overflow-x: auto;
  margin: 0 0 20px;
  position: relative;
}

pre code {
  background: none;
  color: var(--fg);
  padding: 0;
  font-size: 13px;
  line-height: 1.65;
}

pre .lang-label {
  position: absolute;
  top: 8px;
  right: 12px;
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--fg-dim);
  pointer-events: none;
}

/* ---- Syntax Highlighting (minimal) ---- */
.kw  { color: #c084fc; }  /* keywords */
.str { color: #86efac; }  /* strings */
.num { color: #fbbf24; }  /* numbers */
.cmt { color: #64748b; font-style: italic; }  /* comments */
.fn  { color: #67e8f9; }  /* function names */
.typ { color: #f0abfc; }  /* types */
.op  { color: #94a3b8; }  /* operators */
.prop { color: #7dd3fc; } /* properties */

/* ---- Tables ---- */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 20px;
  font-size: 14px;
}

th {
  text-align: left;
  padding: 10px 16px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  color: var(--fg);
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

td {
  padding: 10px 16px;
  border: 1px solid var(--border);
  color: var(--fg-muted);
  vertical-align: top;
}

tr:hover td {
  background: rgba(56, 189, 248, 0.03);
}

/* ---- Lists ---- */
ul, ol {
  margin: 0 0 16px;
  padding-left: 24px;
  color: var(--fg-muted);
}

li {
  margin: 6px 0;
}

li code {
  font-size: 12px;
}

/* ---- Callout Boxes ---- */
.callout {
  padding: 16px 20px;
  border-radius: 8px;
  margin: 0 0 20px;
  border-left: 4px solid;
  font-size: 14px;
}

.callout p:last-child { margin-bottom: 0; }

.callout-info {
  background: var(--accent-soft);
  border-color: var(--accent);
}

.callout-info strong { color: var(--accent); }

.callout-success {
  background: var(--success-soft);
  border-color: var(--success);
}

.callout-success strong { color: var(--success); }

.callout-warning {
  background: var(--warning-soft);
  border-color: var(--warning);
}

.callout-warning strong { color: var(--warning); }

.callout-danger {
  background: var(--error-soft);
  border-color: var(--error);
}

.callout-danger strong { color: var(--error); }

/* ---- Feature / API Cards ---- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  margin: 0 0 24px;
}

.card {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
  transition: border-color 0.15s, transform 0.15s;
}

.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.card h3 {
  margin: 0 0 8px;
  font-size: 15px;
}

.card p {
  margin: 0;
  font-size: 13px;
}

.card a {
  display: inline-block;
  margin-top: 12px;
  font-size: 13px;
  font-weight: 500;
}

/* ---- API Signature Block ---- */
.api-sig {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 16px;
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--fg);
  overflow-x: auto;
}

.api-sig .method-name {
  color: #67e8f9;
  font-weight: 600;
}

.api-sig .param {
  color: #fbbf24;
}

.api-sig .returns {
  color: var(--fg-dim);
}

/* ---- API Parameter Table ---- */
.param-table {
  margin: 0 0 24px;
}

.param-table th:first-child { width: 140px; }
.param-table th:nth-child(2) { width: 100px; }

/* ---- Badge / Tag ---- */
.badge {
  display: inline-block;
  padding: 2px 8px;
  font-size: 11px;
  font-weight: 600;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.3px;
}

.badge-new { background: var(--success-soft); color: var(--success); }
.badge-important { background: var(--warning-soft); color: var(--warning); }
.badge-advanced { background: var(--purple-soft); color: var(--purple); }
.badge-core { background: var(--accent-soft); color: var(--accent); }

/* ---- Diagram / SVG Container ---- */
.diagram {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px;
  margin: 0 0 24px;
  text-align: center;
  overflow-x: auto;
}

.diagram svg {
  max-width: 100%;
  height: auto;
}

/* ---- Breadcrumb ---- */
.breadcrumb {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 24px;
  font-size: 13px;
}

.breadcrumb a {
  color: var(--fg-dim);
}

.breadcrumb a:hover {
  color: var(--accent);
}

.breadcrumb .sep {
  color: var(--fg-dim);
  font-size: 10px;
}

.breadcrumb .current {
  color: var(--fg-muted);
}

/* ---- Footer ---- */
.doc-footer {
  margin-top: 64px;
  padding: 24px 0;
  border-top: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  font-size: 13px;
  color: var(--fg-dim);
}

/* ---- Footer Social Links ---- */
.doc-social {
  flex-basis: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  flex-wrap: wrap;
  padding-top: 14px;
  margin-top: 12px;
  border-top: 1px solid var(--border);
}
.doc-social-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 13px;
  font-size: 12px;
  font-weight: 600;
  border-radius: 14px;
  text-decoration: none;
  background: var(--bg-panel);
  border: 1px solid var(--border);
  color: var(--fg-dim);
  transition: border-color 0.15s, color 0.15s;
}
.doc-social-link:hover { border-color: var(--accent); color: var(--fg); }
.doc-social-link.threads-link:hover { border-color: #a78bfa; color: #a78bfa; }

.doc-footer a {
  color: var(--fg-muted);
}

.doc-footer a:hover {
  color: var(--accent);
}

/* ---- Sidebar Toggle (mobile ≤900px) ---- */
.sidebar-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  touch-action: manipulation;
  flex-shrink: 0;
}
.sidebar-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--fg-muted);
  border-radius: 2px;
  position: relative;
  transition: background 0.2s;
}
.sidebar-toggle span::before,
.sidebar-toggle span::after {
  content: '';
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  background: var(--fg-muted);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.2s;
}
.sidebar-toggle span::before { top: -6px; }
.sidebar-toggle span::after  { top: 6px; }
.sidebar-toggle.open span { background: transparent; }
.sidebar-toggle.open span::before { transform: translateY(6px) rotate(45deg); background: var(--accent); }
.sidebar-toggle.open span::after  { transform: translateY(-6px) rotate(-45deg); background: var(--accent); }

.sidebar-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  top: var(--header-height);
  background: rgba(0,0,0,0.5);
  z-index: 49;
  -webkit-backdrop-filter: blur(2px);
  backdrop-filter: blur(2px);
}
.sidebar-backdrop.open { display: block; }

/* ---- Mobile Nav Hamburger ---- */
.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: 8px;
  margin-left: auto;
  background: none;
  border: none;
  cursor: pointer;
  touch-action: manipulation;
  flex-shrink: 0;
}
.nav-hamburger span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--fg-muted);
  border-radius: 2px;
  transition: transform 0.2s, opacity 0.2s;
}
.nav-hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---- Mobile Nav Dropdown ---- */
.doc-mobile-nav {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  background: var(--bg-panel);
  border-bottom: 1px solid var(--border);
  padding: 8px 16px 16px;
  flex-direction: column;
  gap: 2px;
  z-index: 98;
  box-shadow: 0 8px 24px rgba(0,0,0,0.3);
}
.doc-mobile-nav.open { display: flex; }
.doc-mobile-nav a {
  padding: 11px 12px;
  color: var(--fg-muted);
  font-size: 14px;
  font-weight: 500;
  border-radius: 6px;
  text-decoration: none;
  transition: color 0.15s, background 0.15s;
}
.doc-mobile-nav a:hover { color: var(--fg); background: var(--accent-soft); }
.doc-mobile-nav a.active { color: var(--accent); }

/* ---- Scroll Progress Bar ---- */
.doc-scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--purple));
  z-index: 200;
  pointer-events: none;
  transition: width 0.1s linear;
  box-shadow: 0 0 8px var(--accent-glow);
}

/* ---- Copy Button (class-based) ---- */
.doc-copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  padding: 3px 10px;
  font-size: 11px;
  font-weight: 600;
  background: rgba(56,189,248,0.1);
  color: var(--accent);
  border: 1px solid rgba(56,189,248,0.2);
  border-radius: 4px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s;
  font-family: var(--font-sans);
}
.doc-copy-btn:hover {
  background: rgba(56,189,248,0.2);
}

/* ---- Reading Progress Badges ---- */
.doc-read-check {
  margin-left: auto;
  font-size: 11px;
  color: var(--success);
  font-weight: 700;
  flex-shrink: 0;
}
.sidebar-link {
  display: flex;
  align-items: center;
}
.sidebar-link.doc-read {
  color: var(--fg-muted);
}

/* ---- Reading Time Badge ---- */
.doc-reading-time {
  display: inline-block;
  font-size: 12px;
  color: var(--fg-dim);
  margin-bottom: 24px;
  padding: 2px 10px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 10px;
  font-weight: 500;
}

/* ---- Back to Top Button ---- */
.doc-back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 40px;
  height: 40px;
  border: none;
  background: var(--bg-panel);
  color: var(--fg-muted);
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 18px;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s, border-color 0.15s;
  z-index: 90;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}
.doc-back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
}
.doc-back-to-top:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-2px);
}

/* ---- Search Modal Overlay ---- */
.doc-search-overlay {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 15vh;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s;
}
.doc-search-overlay.visible {
  opacity: 1;
  pointer-events: auto;
}

.doc-search-modal {
  width: 560px;
  max-width: 90vw;
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: 0 16px 48px rgba(0,0,0,0.5);
  overflow: hidden;
}

.doc-search-header {
  display: flex;
  align-items: center;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  gap: 12px;
}

.doc-search-input {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  color: var(--fg);
  font-size: 15px;
  font-family: var(--font-sans);
}
.doc-search-input::placeholder {
  color: var(--fg-dim);
}

.doc-search-kbd {
  font-family: var(--font-sans);
  font-size: 11px;
  padding: 2px 6px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--fg-dim);
  flex-shrink: 0;
}

.doc-search-results {
  max-height: 320px;
  overflow-y: auto;
  padding: 8px;
}
.doc-search-results::-webkit-scrollbar { width: 4px; }
.doc-search-results::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }

.doc-search-result {
  display: flex;
  flex-direction: column;
  padding: 10px 12px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.1s;
}
.doc-search-result:hover,
.doc-search-result.selected {
  background: var(--accent-soft);
}
.doc-search-result-section {
  font-size: 10px;
  font-weight: 600;
  color: var(--fg-dim);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.doc-search-result-title {
  font-size: 14px;
  color: var(--fg);
  font-weight: 500;
}

.doc-search-empty {
  padding: 24px 16px;
  text-align: center;
  color: var(--fg-dim);
  font-size: 13px;
}

.doc-search-footer {
  display: flex;
  gap: 16px;
  padding: 10px 16px;
  border-top: 1px solid var(--border);
  font-size: 11px;
  color: var(--fg-dim);
}
.doc-search-footer kbd {
  font-family: var(--font-sans);
  font-size: 10px;
  padding: 1px 5px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--fg-dim);
  margin: 0 2px;
}

/* ---- Responsive ---- */
@media (max-width: 900px) {
  .sidebar-toggle { display: flex; }
  .doc-sidebar {
    transform: translateX(-100%);
    transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: none;
    z-index: 55;
  }
  .doc-sidebar.open {
    transform: translateX(0);
    box-shadow: 4px 0 24px rgba(0,0,0,0.35);
  }
  .doc-content { margin-left: 0; padding: 24px 20px 60px; }
  .card-grid { grid-template-columns: 1fr; }
  h1 { font-size: 26px; }
  h2 { font-size: 19px; }
  table { font-size: 13px; }
  td, th { padding: 8px 12px; }
}

@media (max-width: 600px) {
  .doc-header nav { display: none; }
  .doc-header .search-box { display: none; }
  .nav-hamburger { display: flex; }
  .doc-content { padding: 20px 16px 60px; }
  pre { font-size: 12px; padding: 12px 14px; }
  .api-sig { font-size: 13px; }
  .doc-footer { flex-direction: column; gap: 8px; text-align: center; }
  .doc-back-to-top { bottom: 16px; right: 16px; }
  .doc-search-modal { max-width: 95vw; }
}

/* ---- Print ---- */
@media print {
  .doc-header, .doc-sidebar, .doc-scroll-progress,
  .doc-back-to-top, .doc-search-overlay,
  .doc-copy-btn, .nav-hamburger, .doc-mobile-nav,
  .sidebar-toggle, .sidebar-backdrop { display: none !important; }
  .doc-content { margin-left: 0; padding: 20px; max-width: 100%; }
  body { background: #fff; color: #000; }
  h1, h2, h3, h4, strong { color: #000; }
  p, li, td { color: #333; }
  a { color: #0066cc; }
  code { background: #f0f0f0; color: #333; border-color: #ccc; }
  pre { background: #f8f8f8; border-color: #ddd; }
  pre code { color: #333; }
  .card { border-color: #ccc; }
  .badge { border: 1px solid #ccc; }
}